In the last few years it has become increasingly common for a hand-held wireless terminal (e.g., a notebook computer, a supermarket scanner, a warehouse data-entry device, etc.) to be equipped with a wireless telecommunications capability to enable the wireless terminal to transmit information to a host system, or to receive information from the host system, or both. For example, a worker in a warehouse can carry a wireless terminal to assist a host system in monitoring inventory. The host system can transmit by radio to the wireless terminal a request to the worker to check how many units of a particular item are in the warehouse. After the worker has counted the number of units the worker can enter the number into the wireless terminal, which relays the number back to the host system by radio.
Although some wireless terminals (e.g., cellular telephones, cordless telephones, etc.) are manufactured with a permanent, integrated radio, other wireless terminals (e.g., hand-held data-entry devices, notebook computers, etc.) are not. One advantage of manufacturing a wireless terminal without a permanent radio is that it enables the end-user to select a radio that is appropriate for the environment in which the wireless terminal is to operate.
The wireless terminals that are manufactured without an integrated radio are, however, usually manufactured with the capability to connect to a radio. Typically, the connection is made through an industry-standard specification that prescribes both the mechanical and electrical interface. Currently, the PCMCIA "PC Card" interface is the standard to which almost all wireless terminals are designed.
The PC Card specification prescribes a slot in the wireless terminal for receiving a credit-card-shaped radio and a 68-pin electrical connector on both the radio card and in the slot so that the radio card and the wireless terminal can share power, ground and signaling. The PC Card interface also specifies the voltage, timing, and signaling protocol on each lead of the 68-pin electrical connector.
Typically, a PC radio card has a built-in antenna for transmitting and receiving signals. FIG. 1 depicts a diagram of a top view of a typical radio card. As shown in FIG. 1, radio card 100 comprises radio 107, which is electrically connected to antenna 103 via lead 105, all of which are mounted on printed circuit board 101. Typically, lead 105 is printed on printed circuit board 101. Radio card 100 also comprises connector 109, which is the 68-pin electrical connector between radio 107 and the circuitry within the wireless terminal.
FIG. 2 depicts a diagram of a top view of wireless terminal 201 and radio card 100 when radio card 100 has been properly inserted into wireless terminal 201. FIG. 3 depicts a side view of FIG. 2. When radio card 100 is seated into wireless terminal 201, that portion of radio card 100 comprising antenna 103 typically projects out of wireless terminal 201 because it enables antenna 103 to radiate and receive signals unhindered by the housing of wireless terminal 201.
There are, however, two distinct disadvantages to having the radio card project out of the wireless terminal. First, the fact that radio card 100 extends beyond the housing of wireless terminal 201 greatly increases the likelihood that the radio card or the wireless terminal or both will be damaged if the wireless terminal is accidentally dropped and lands on radio card 100. Second, many wireless terminals have one or more doors (e.g., door 203) that cover the slot into which a PC Card is inserted. The fact that radio card 100 extends beyond the housing of wireless terminal 201 precludes the closing of door 203, which allows dirt and dust to enter the wireless terminal.
Therefore, the need exists for an improved radio card design or terminal design or both that does not increase the likelihood that the radio card or wireless terminal or both will be damaged if the wireless terminal is accidentally dropped and that does not allow dirt and dust to enter the wireless terminal. Furthermore, the improved radio card design or terminal design or both should exhibit favorable radio propagation characteristics.